敏捷光学卫星无控几何精度提升途径探讨

Discussion of Geo-location Accuracy Increasing Methods of Agile Satellite Without Ground Control Points

针对敏捷光学卫星无控制点几何精度,提出了区分高频和低频姿态误差、同时考虑定位误差的精化传播模型,通过仿真分析得出了低频姿态误差及姿态稳定度误差对定位精度的影响规律,并以满足30m平面定位精度和1:50 000比例尺测图要求为例,进行了定位误差分配和定位精度预估,提出了提高无控定位精度的措施。结果表明:星敏感器低频姿态角误差主要造成了水平位置方向的系统误差,但其在高程位置方向的系统误差可以通过卫星前后对称俯仰成像进行消除。当定位精度要求30m量级时,星敏感器低频误差和夹角稳定性不需要在现有卫星水平上加严控制,但是应尽量采用大基高比,同时采用异侧对称立体成像方式,避免系统性低频姿态误差带来额外的高程误差;当精度要求满足1:50 000时,应配置0.9″精度星敏感器,200Hz以上高频姿态测量设备和在轨夹角检测装置,同时将低频误差有效控制在5″以内等,以满足15m平面,6m高程的精度要求。

In light of geo-location accuracy of the agile optical satellite,this paper proposes a fine locating propagation model which distinguishes the high-frequency and low-frequency attitude errors,as well as considering the system design parameters.By the simulation analysis,the influence law of the low-frequency error and attitude stability error to the final location accuracy is presented.Taking the 30 mlocation accuracy and the map scale of 1∶50 000 as an example,the value of index is analyzed and the methods of increasing geo-location accuracy is put forward.The result is that the low-frequency errors mainly impact the horizontal geo-location accuracy.The30 maccuracy would be met with no more control to the attitude problem,but only imaging with larger and symmetric intersection angles.If the satellite attitude measurement accuracy reaches 0.9″and the 200 Hz high-frequency attitude measurement equipment and the on-orbit angle measurement equipment are used between the star track and the camera,also with the control of the low-frequency errors within 5″,the accuracy for the map scale of 1∶50 000（plan 15 mand height 6m）would be met.